Subject: [PATCH] Add guards around [nfsidmap] usages of [sysconf].

sysconf(_SC_GETPW_R_SIZE_MAX) and sysconf(_SC_GETGR_R_SIZE_MAX)
return -1 on musl, which causes either segmentation faults or ENOMEM
errors.

Replace all usages of sysconf with dedicated methods that guard against
a result of -1.

Signed-off-by: Bogdan-Cristian Tătăroiu <[email protected]>
---
support/nfsidmap/gums.c | 4 ++--
support/nfsidmap/libnfsidmap.c | 4 ++--
support/nfsidmap/nfsidmap_common.c | 16 ++++++++++++++++
support/nfsidmap/nfsidmap_private.h | 2 ++
support/nfsidmap/nss.c | 8 ++++----
support/nfsidmap/regex.c | 9 +++++----
support/nfsidmap/static.c | 5 +++--
7 files changed, 34 insertions(+), 14 deletions(-)

diff --git a/support/nfsidmap/gums.c b/support/nfsidmap/gums.c
index 1d6eb318..e94a4c50 100644
--- a/support/nfsidmap/gums.c
+++ b/support/nfsidmap/gums.c
@@ -475,7 +475,7 @@ static int translate_to_uid(char *local_uid, uid_t *uid, uid_t *gid)
int ret = -1;
struct passwd *pw = NULL;
struct pwbuf *buf = NULL;
- size_t buflen = sysconf(_SC_GETPW_R_SIZE_MAX);
+ size_t buflen = get_pwnam_buflen();

buf = malloc(sizeof(*buf) + buflen);
if (buf == NULL)
@@ -501,7 +501,7 @@ static int translate_to_gid(char *local_gid, uid_t *gid)
struct group *gr = NULL;
struct group grbuf;
char *buf = NULL;
- size_t buflen = sysconf(_SC_GETGR_R_SIZE_MAX);
+ size_t buflen = get_grnam_buflen();
int ret = -1;

do {
diff --git a/support/nfsidmap/libnfsidmap.c b/support/nfsidmap/libnfsidmap.c
index f8c36480..e1475879 100644
--- a/support/nfsidmap/libnfsidmap.c
+++ b/support/nfsidmap/libnfsidmap.c
@@ -457,7 +457,7 @@ int nfs4_init_name_mapping(char *conffile)

nobody_user = conf_get_str("Mapping", "Nobody-User");
if (nobody_user) {
- size_t buflen = sysconf(_SC_GETPW_R_SIZE_MAX);
+ size_t buflen = get_pwnam_buflen();
struct passwd *buf;
struct passwd *pw = NULL;
int err;
@@ -478,7 +478,7 @@ int nfs4_init_name_mapping(char *conffile)

nobody_group = conf_get_str("Mapping", "Nobody-Group");
if (nobody_group) {
- size_t buflen = sysconf(_SC_GETGR_R_SIZE_MAX);
+ size_t buflen = get_grnam_buflen();
struct group *buf;
struct group *gr = NULL;
int err;
diff --git a/support/nfsidmap/nfsidmap_common.c b/support/nfsidmap/nfsidmap_common.c
index 4d2cb14f..310c68f0 100644
--- a/support/nfsidmap/nfsidmap_common.c
+++ b/support/nfsidmap/nfsidmap_common.c
@@ -116,3 +116,19 @@ int get_reformat_group(void)

return reformat_group;
}
+
+size_t get_pwnam_buflen(void)
+{
+ size_t buflen = sysconf(_SC_GETPW_R_SIZE_MAX);
+ if (buflen == -1)
+ buflen = 16384;
+ return buflen;
+}
+
+size_t get_grnam_buflen(void)
+{
+ size_t buflen = sysconf(_SC_GETGR_R_SIZE_MAX);
+ if (buflen == -1)
+ buflen = 16384;
+ return buflen;
+}
diff --git a/support/nfsidmap/nfsidmap_private.h b/support/nfsidmap/nfsidmap_private.h
index a5cb6dda..234ca9d4 100644
--- a/support/nfsidmap/nfsidmap_private.h
+++ b/support/nfsidmap/nfsidmap_private.h
@@ -40,6 +40,8 @@ struct conf_list *get_local_realms(void);
void free_local_realms(void);
int get_nostrip(void);
int get_reformat_group(void);
+size_t get_pwnam_buflen(void);
+size_t get_grnam_buflen(void);

typedef enum {
IDTYPE_USER = 1,
diff --git a/support/nfsidmap/nss.c b/support/nfsidmap/nss.c
index 0f43076e..3fc045dc 100644
--- a/support/nfsidmap/nss.c
+++ b/support/nfsidmap/nss.c
@@ -91,7 +91,7 @@ static int nss_uid_to_name(uid_t uid, char *domain, char *name, size_t len)
struct passwd *pw = NULL;
struct passwd pwbuf;
char *buf;
- size_t buflen = sysconf(_SC_GETPW_R_SIZE_MAX);
+ size_t buflen = get_pwnam_buflen();
int err = -ENOMEM;

buf = malloc(buflen);
@@ -119,7 +119,7 @@ static int nss_gid_to_name(gid_t gid, char *domain, char *name, size_t len)
struct group *gr = NULL;
struct group grbuf;
char *buf;
- size_t buflen = sysconf(_SC_GETGR_R_SIZE_MAX);
+ size_t buflen = get_grnam_buflen();
int err;

if (domain == NULL)
@@ -192,7 +192,7 @@ static struct passwd *nss_getpwnam(const char *name, const char *domain,
{
struct passwd *pw;
struct pwbuf *buf;
- size_t buflen = sysconf(_SC_GETPW_R_SIZE_MAX);
+ size_t buflen = get_pwnam_buflen();
char *localname;
int err = ENOMEM;

@@ -301,7 +301,7 @@ static int _nss_name_to_gid(char *name, gid_t *gid, int dostrip)
struct group *gr = NULL;
struct group grbuf;
char *buf, *domain;
- size_t buflen = sysconf(_SC_GETGR_R_SIZE_MAX);
+ size_t buflen = get_grnam_buflen();
int err = -EINVAL;
char *localname = NULL;
char *ref_name = NULL;
diff --git a/support/nfsidmap/regex.c b/support/nfsidmap/regex.c
index 8424179f..ea094b95 100644
--- a/support/nfsidmap/regex.c
+++ b/support/nfsidmap/regex.c
@@ -46,6 +46,7 @@

#include "nfsidmap.h"
#include "nfsidmap_plugin.h"
+#include "nfsidmap_private.h"

#define CONFIG_GET_STRING nfsidmap_config_get
extern const char *nfsidmap_config_get(const char *, const char *);
@@ -95,7 +96,7 @@ static struct passwd *regex_getpwnam(const char *name, const char *UNUSED(domain
{
struct passwd *pw;
struct pwbuf *buf;
- size_t buflen = sysconf(_SC_GETPW_R_SIZE_MAX);
+ size_t buflen = get_pwnam_buflen();
char *localname;
size_t namelen;
int err;
@@ -175,7 +176,7 @@ static struct group *regex_getgrnam(const char *name, const char *UNUSED(domain)
{
struct group *gr;
struct grbuf *buf;
- size_t buflen = sysconf(_SC_GETGR_R_SIZE_MAX);
+ size_t buflen = get_grnam_buflen();
char *localgroup;
char *groupname;
size_t namelen;
@@ -366,7 +367,7 @@ static int regex_uid_to_name(uid_t uid, char *domain, char *name, size_t len)
struct passwd *pw = NULL;
struct passwd pwbuf;
char *buf;
- size_t buflen = sysconf(_SC_GETPW_R_SIZE_MAX);
+ size_t buflen = get_pwnam_buflen();
int err = -ENOMEM;

buf = malloc(buflen);
@@ -392,7 +393,7 @@ static int regex_gid_to_name(gid_t gid, char *UNUSED(domain), char *name, size_t
struct group grbuf;
char *buf;
const char *name_prefix;
- size_t buflen = sysconf(_SC_GETGR_R_SIZE_MAX);
+ size_t buflen = get_grnam_buflen();
int err;
char * groupname = NULL;

diff --git a/support/nfsidmap/static.c b/support/nfsidmap/static.c
index 8ac4a398..395cac06 100644
--- a/support/nfsidmap/static.c
+++ b/support/nfsidmap/static.c
@@ -44,6 +44,7 @@
#include "conffile.h"
#include "nfsidmap.h"
#include "nfsidmap_plugin.h"
+#include "nfsidmap_private.h"

/*
* Static Translation Methods
@@ -98,7 +99,7 @@ static struct passwd *static_getpwnam(const char *name,
{
struct passwd *pw;
struct pwbuf *buf;
- size_t buflen = sysconf(_SC_GETPW_R_SIZE_MAX);
+ size_t buflen = get_pwnam_buflen();
char *localname;
int err;

@@ -149,7 +150,7 @@ static struct group *static_getgrnam(const char *name,
{
struct group *gr;
struct grbuf *buf;
- size_t buflen = sysconf(_SC_GETGR_R_SIZE_MAX);
+ size_t buflen = get_grnam_buflen();
char *localgroup;
int err;

--
2.44.1